Abstract: Objective  To investigate the effects of high-altitude environment on cognitive function and ultrastructure in CA1 region of the hippocampus of Wistar rats in sleep deprivation (SD).  Methods  SD was induced in Wistar rats by employing "flower pot" technique. Sixty-four rats were randomly divided into 2 groups: Lanzhou group (at an altitude of 1520 m) and Kekexili group (at an altitude of 4767 m), and each group was further divided into 4 subgroups according to the time of SD (0, 1, 3 and 5 d). The behaviors of rats were studied by Morris water maze test at given time points. The ultrastructure of hippocampal neurons was observed by transmission electron microscope (TEM).  Results  1) Compared with Lanzhou group, rat behavior of Kekexili group presented excitement-irritation-suppression changes with the extension of SD time, but the extent was weakened gradually, and time of sleepiness increased obviously. 2) Compared with Lanzhou group, neurons in CA1 region of hippocampus showed enlarged cell body, disappeared nuclear membrane, shrunken nuclei and decreased organelle. End-feet of glia cells sticking to capillaries swelled and ruptured, and the typical synaptic structure disappeared. 3) Morris water maze test: as compared with Lanzhou group, the escape latency of Kekexili group prolonged (P < 0.05, for all), the ability of distance exploration increased (P < 0.05, for all), and the times across plot decreased (P < 0.05, for all) in 1, 3 and 5 d of SD.  Conclusions  High-altitude environment may significantly influence the cognitive function of rats in SD, and there was close correlation between the cognitive disorders and the changes in the ultrastructure of hippocampal CA1 region.

Key words: Altitude, Sleep deprivation, Memory disorders, Maze learning, Hippocampus, Synapses, Microscopy, electron, transmission, Disease models, animal

摘要： 目的 探讨高原环境对睡眠剥夺大鼠学习记忆能力和海马CA1 区超微结构的影响。方法 采用小平台水环境法建立大鼠睡眠剥夺模型，并随机分为兰州组（海拔1520 m）和可可西里组（海拔4767 m）；Morris 水迷宫实验评价不同高原环境对大鼠空间分辨学习能力的影响，透射电子显微镜观察其海马CA1 区超微结构变化。结果 与兰州组相比，可可西里组大鼠随着睡眠剥夺时间的延长，呈现兴奋-激惹-抑制变化，但程度逐渐减弱且低头思睡时间明显增多；超微结构观察海马CA1 区神经元胞体明显肿胀，核膜消失，胞核缩小，细胞器数目减少，微血管周围胶质足板肿胀、破裂，典型突触结构消失。睡眠剥夺第1，3 和5 天，可可西里组大鼠逃避潜伏期延长（均P < 0.05）、游泳路程增加（均P < 0.05），而穿越平台次数减少（均P < 0.05）。结论 高原环境可使睡眠剥夺大鼠学习记忆能力进一步降低，其机制可能与海马CA1区超微结构变化有关。

关键词: 高海拔, 睡眠剥夺, 记忆障碍, 迷宫学习, 海马, 突触, 显微镜检查, 电子, 透射, 疾病模型, 动物